Induction of peripheral lymph node addressin in human nasal mucosa with eosinophilic chronic rhinosinusitis

Eosinophilic chronic rhinosinusitis (ECRS) is characterised by formation of nasal polyps with prominent eosinophilic infiltration; however, how eosinophils are recruited in this pathological setting remains unclear. In the present study, we carried out quantitative immunohistochemical analysis of nasal polyps associated with ECRS (n=30) and non-ECRS (n=30) to evaluate expression of an L-selectin ligand peripheral lymph node addressin (PNAd) on vascular endothelial cells. We found that PNAd was induced primarily on the luminal surface of venular vessels present in nasal mucosa in both ECRS and non-ECRS, while the number of PNAd-expressing vessels in ECRS significantly exceeded that seen in non-ECRS. Moreover, the number of eosinophils attached to the luminal surface of PNAd-expressing vessels in ECRS was significantly greater than that in non-ECRS, while the number of neutrophils and lymphocytes attached did not differ significantly between conditions. Furthermore, eosinophils, which express cell surface L-selectin, adhered to PNAd-expressing Chinese hamster ovary (CHO) cells in a calcium-dependent manner, and that adhesion was significantly inhibited by pretreatment of eosinophils with DREG-56, an anti-human L-selectin monoclonal antibody. These findings combined suggest that interaction between L-selectin and PNAd plays at least a partial role in eosinophil recruitment in human nasal mucosa with ECRS.

Complementary Role of GlcNAc6ST2 and GlcNAc6ST3 in Synthesis of CL40-Reactive Sialylated and Sulfated Glycans in the Mouse Pleural Mesothelium

Sialyl 6-sulfo Lewis X (6-sulfo sLe^X) and its derivative sialyl 6-sulfo N-acetyllactosamine (LacNAc) are sialylated and sulfated glycans of sialomucins found in the high endothelial venules (HEVs) of secondary lymphoid organs. A component of 6-sulfo sLe^X present in the core 1-extended O-linked glycans detected by the MECA-79 antibody was previously shown to exist in the lymphoid aggregate vasculature and bronchial mucosa of allergic and asthmatic lungs. The components of 6-sulfo sLe^X in pulmonary tissues under physiological conditions remain to be analyzed. The CL40 antibody recognizes 6-sulfo sLe^X and sialyl 6-sulfo LacNAc in O-linked and N-linked glycans, with absolute requirements for both GlcNAc-6-sulfation and sialylation. Immunostaining of normal mouse lungs with CL40 was performed and analyzed. The contribution of GlcNAc-6-O-sulfotransferases (GlcNAc6STs) to the synthesis of the CL40 epitope in the lungs was also elucidated. Here, we show that the expression of the CL40 epitope was specifically detected in the mesothelin-positive mesothelium of the pulmonary pleura. Moreover, GlcNAc6ST2 (encoded by Chst4) and GlcNAc6ST3 (encoded by Chst5), but not GlcNAc6ST1 (encoded by Chst2) or GlcNAc6ST4 (encoded by Chst7), are required for the synthesis of CL40-positive glycans in the lung mesothelium. Furthermore, neither GlcNAc6ST2 nor GlcNAc6ST3 is sufficient for in vivo expression of the CL40 epitope in the lung mesothelium, as demonstrated by GlcNAc6ST1/3/4 triple-knock-out and GlcNAc6ST1/2/4 triple-knock-out mice. These results indicate that CL40-positive sialylated and sulfated glycans are abundant in the pleural mesothelium and are synthesized complementarily by GlcNAc6ST2 and GlcNAc6ST3, under physiological conditions in mice.

Role of sialyl 6-sulfo Lewis X in antitumor immunity against oral squamous cell carcinoma

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) reportedly play a pivotal role in antitumor immunity against oral squamous cell carcinoma (OSCC); however, mechanisms governing TIL recruitment to OSCC tissues remain to be clarified. This study was undertaken to assess a potential association between TILs and high endothelial venule (HEV)-like vessels that express sialyl 6-sulfo Lewis X (LeX).

METHODS

OSCC tissue sections (n=41) were subjected to immunohistochemistry for sialyl 6-sulfo LeX and CD34 to allow quantitation of HEV-like vessels. Triple immunohistochemistry for sialyl 6-sulfo LeX and either CD3 and CD20 or CD4 and CD8 was conducted to determine which lymphocyte subset is more closely associated with HEV-like vessels.

RESULTS

HEV-like vessels expressing sialyl 6-sulfo LeX were detected in 27 of 41 (65.9%) OSCC cases, and these vessels were more frequently found in early disease (T1/T2 stages) compared with advanced (T3/T4) stages. The number of T cells attached to the inner surface of these HEV-like vessels was significantly greater than that of B cells, while the number of CD4⁺ helper T cells and CD8⁺ cytotoxic T cells did not differ significantly. Interestingly, sialyl 6-sulfo LeX was also expressed on the membrane of a fraction of OSCC cells, and CD8⁺ cytotoxic T cells were almost exclusively found attached to these carcinoma cells.

CONCLUSIONS

Sialyl 6-sulfo LeX is displayed not only on HEV-like vessels but also on OSCC cells and may potentially function in antitumor immunity against OSCC.